[PATCH AUTOSEL 4.14 31/34] bpf: bpf_setsockopt: reset sock dst on SO_MARK changes

Sasha Levin
2019-02-13T02:40:42Z

From: Peter Oskolkov <posk@google.com>

[ Upstream commit f4924f24da8c7ef64195096817f3cde324091d97 ]

In sock_setsockopt() (net/core/sock.h), when SO_MARK option is used
to change sk_mark, sk_dst_reset(sk) is called. The same should be
done in bpf_setsockopt().

Fixes: 8c4b4c7e9ff0 ("bpf: Add setsockopt helper function to bpf")
Reported-by: Maciej Żenczykowski <maze@google.com>
Signed-off-by: Peter Oskolkov <posk@google.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Reviewed-by: Maciej Żenczykowski <maze@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/core/filter.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/net/core/filter.c b/net/core/filter.c
index a8a9ff0568b9..41ede90fc28f 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -3102,7 +3102,10 @@ BPF_CALL_5(bpf_setsockopt, struct bpf_sock_ops_kern *, bpf_sock,
sk->sk_rcvlowat = val ? : 1;
break;
case SO_MARK:
- sk->sk_mark = val;
+ if (sk->sk_mark != val) {
+ sk->sk_mark = val;
+ sk_dst_reset(sk);
+ }
break;
default:
ret = -EINVAL;
--
2.19.1